WASHINGTON (AP) — President Barack Obama, defending his foreign policy record at a time of anti-American rage in the Muslim world, fired back at suggestions from Republican Mitt Romney that the president has been weak with allies and enemies alike.

In an interview airing the night before Obama meets with other world leaders at the United Nations, the president said, "If Gov. Romney is suggesting that we should start another war, he should say so."

It was Obama's most direct rebuttal yet to persistent skepticism by his White House rival on his handling of an unraveling situation in the Middle East. Romney has charged the U.S. stance has been marred by miscalculations, mixed messages and appeasement.

The foreign policy arguments come as both candidates sharpen their strategy just six weeks ahead of Election Day. Speaking to reporters on a flight to Colorado Sunday night, Romney acknowledged he was slipping behind Obama in several swing states and said he would spend more time with voters in the coming weeks.

"I think the fundraising season is probably a little quieter going forward," he said following a weekend largely devoted to raising money in California.

Facing Republican fears that his campaign is moving in the wrong direction, Romney huddled earlier in the day with his top advisers, preparing for next month's debates and crafting a more aggressive strategy.

"I don't pay a lot of attention to the day-to-day polls. They change a great deal," Romney said. "And I know that in the coming six weeks they're very unlikely to stay where they are today."

Obama Is launching a new campaign offensive Monday with his first television advertisement targeting Romney's comments about Americans who don't pay income taxes. The ad, which was to start running in swing state Ohio, argues that Romney should stop attacking others on taxes and "come clean" on his own.

The ad uses Romney's comments to wealthy donors that 47 percent of Americans don't pay income taxes, believe they are victims and feel entitled to government assistance. It shows Romney saying, "My job is not to worry about those people."

The 30-second spot signals that Obama will keep making the wealthy Romney's taxes a campaign issue even after the Republican released a second year of information about his personal finances on Friday.

Romney, who has criticized Obama's response to unrest in Syria and anti-American protests across the Muslim world, broadened his reproach to include Israel. He said Obama's failure to schedule a meeting with Israeli Prime Minister Benjamin Netanyahu during the annual U.N. gathering this week "sends a message throughout the Middle East that somehow we distance ourselves from our friends."

The White House has said scheduling precluded a meeting between the two leaders, who won't be in New York at the same time. But Obama pushed back on the notion that he feels pressure from Netanyahu, dismissing as noise the Israeli leader's calls for the U.S. to lay out a "red line" that Iran's nuclear program mustn't cross to avoid American military intervention.

"When it comes to our national security decisions, any pressure that I feel is simply to do what's right for the American people," Obama said. "And I am going to block out any noise that's out there. "

In a wide-ranging interview conducted the day after U.S. Ambassador to Libya Chris Stevens was killed in an attack on Benghazi, Obama defended his foreign policy successes, noting he'd followed through on a commitment to end the war in Iraq and had nabbed al-Qaida leader Osama bin Laden.

He also waxed optimistic that winning a second term would give him a mandate to overcome obstructionism from congressional Republicans whose No. 1 goal, he said, has been to prevent his re-election.

"My expectation is, my hope is that that's no longer their number one priority," Obama said. "I'm hoping that after the smoke clears and the election season's over that that spirit of cooperation comes more to the fore."

Romney, in an interview conducted last week, sought to deflect attention from his running mate, Wisconsin Rep. Paul Ryan, over their differences in Medicare policy: "I'm the guy running for president, not him."

While reaffirming his commitment to lowering all income tax rates by 20 percent, Romney expressed no unease about his refusal to offer specifics, such as which loopholes and deductions he'd eliminate to pay for the cuts.

"The devil's in the details. The angel is in the policy, which is creating more jobs," Romney said, adding that he doesn't want to see overall government revenue reduced.

Addressing the seemingly unshakable charge of flip-flopping on policy issues, Romney pointed the finger at Obama, noting his changes of heart on gay marriage and military tribunals for terrorism suspects.

"Have I found some things I thought would be effective turned out not to be effective? Absolutely," Romney said. "You don't learn from experience, you don't learn from your mistakes —why, you know, you ought to be fired."

The series of interviews also offered glimpses into both candidates' personal habits, including their late-night routines. Romney said his nightly prayer is a time to connect both with the divine and with his own thoughts, and said he asks God mainly for wisdom and understanding.

Obama, describing himself as "a night guy," said that after first lady Michelle Obama and their daughters retire around 10 p.m., he hunkers down for reading, writing and occasionally a moment alone on the Truman Balcony, with the Washington Monument and Jefferson Memorial in view.

"Those are moments of reflection that, you know, help gird you for the next challenge and the next day," Obama said.

The "60 Minutes" interviews came as Romney's campaign strove to turn the page on a week of public stumbles and Republican hand-wringing. On the flight to Colorado, Romney said he's looking forward to next month's debates to help reverse his slide, which he attributed to Obama's aggressive advertising.

"He's trying to fool people into thinking that I think things I don't," Romney said of the president. "And that ends I think during the debates."

Romney blamed his fundraising focus on Obama's decision to bypass traditional spending limits during the 2008 campaign. "I'd far rather be spending my time out in the key swing states campaigning door to door if necessary, but in rallies and various meetings," he said. "But fundraising is part of politics when your opponent decides not to live by the federal spending limits."

After Colorado, Romney was to begin a three-day bus tour in Ohio on Monday followed by a stop in Virginia — states that Obama won in 2008 but that Republicans claimed four years earlier.

While national polls remain tight, polls in several of the most closely watched states, including Colorado, suggest Obama has opened narrow leads. Obama won Colorado by 9 points four years ago, but the state went to a Republican in the previous three presidential elections.

Obama took a rare weekend break from the campaigning ahead of his U.N. address Tuesday, but dispatched top allies to the Sunday talk shows.